A reversible lane is a lane where it allows traffic direction changed according to a predetermined configuration. Typically, a reversible lane is chosen as a lane between two lanes whose traffic directions reverse to each other for improving traffic flow during rush hours. For notifying drivers of the reversible lane, prior dividing columns are placed on one edge side of the reversible lane in a row for separating the reversible lane and its neighboring lane whose traffic directions are opposite. The prior dividing columns should be moved by manpower. For example, if the westward traffic flow is heavier than the eastward traffic flow, the dividing columns should be disposed between the reversible lane and the eastward lane by manpower for the purpose of notifying drivers of westward direction of the reversible lane. On the contrary, if the eastward traffic flow is heavier than the westward traffic flow, the dividing columns should be moved to positions between the reversible lane and the westward lane by manpower for the purpose of notifying drivers of the traffic eastward direction of the reversible lane. However, not only it is inconvenient for the movement of the dividing columns by manpower, but is dangerous for people who move the dividing columns across the lanes back and forth. Moreover, the dividing columns are easy to be toppled down and easy to be removed by the third party or any other unexpectedly force such as a wind force, by which it not only causes the dividing columns being ineffective for lane dividing, but also causes the dividing columns being lost and destroyed. It thus brings traffic hazard.